Thermally assisted recording head having recessed waveguide with near field transducer and methods of making same

ABSTRACT

An apparatus according to one embodiment includes a near field transducer comprising a conductive metal film; and an optical waveguide for illumination of the near field transducer, a light guiding core layer of the optical waveguide being spaced from the near field transducer by less than about 100 nanometers and greater than 0 nanometers, wherein a longitudinal axis of the optical waveguide is substantially perpendicular to an air bearing surface.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/347,084, filed Dec. 31, 2008, and which is herein incorporated byreference.

FIELD OF THE INVENTION

The present invention relates to data storage systems, and moreparticularly, this invention relates to write heads with near fieldtransducers for thermally assisted recording.

BACKGROUND OF THE INVENTION

The heart of a computer is a magnetic disk drive which typicallyincludes a rotating magnetic disk, a slider that has read and writeheads, a suspension arm above the rotating disk and an actuator arm thatswings the suspension arm to place the read and/or write heads overselected circular tracks on the rotating disk. The suspension arm biasesthe slider into contact with the surface of the disk when the disk isnot rotating (in some disk drives, there is a load/unload ramp socontact with the disk does not occur); but, when the disk rotates, airis swirled by the rotating disk adjacent an air bearing surface (ABS) ofthe slider causing the slider to ride on an air bearing a slightdistance from the surface of the rotating disk. When the slider rides onthe air bearing the write and read heads are employed for writingmagnetic impressions to and reading magnetic signal fields from therotating disk. The read and write heads are connected to processingcircuitry that operates according to a computer program to implement thewriting and reading functions.

The ongoing quest for higher storage bit densities in magnetic mediaused in disk drives have reduced the size (volume) of data cells to thepoint where the cell dimensions are limited by the grain size of themagnetic material. Although grain size can be reduced further, there isconcern that data stored within the cells is no longer thermally stable,as random thermal fluctuations at ambient temperatures are sufficient toerase data. This state is described as the superparamagnetic limit,which determines the maximum theoretical storage density for a givenmagnetic media. This limit may be raised by increasing the coercivity ofthe magnetic media or lowering the temperature. Lowering the temperatureis not a practical option when designing hard disk drives for commercialand consumer use. Raising the coercivity is a practical solution, butrequires write heads employing higher magnetic moment materials, ortechniques such as perpendicular recording (or both).

One additional solution has been proposed, which employs heat to lowerthe effective coercivity of a localized region on the magnetic mediasurface and writes data within this heated region. The data statebecomes “fixed” upon cooling the media to ambient temperatures. Thistechnique is broadly referred to as “thermally assisted (magnetic)recording”, TAR or TAMR. It can be applied to both longitudinal orperpendicular recording systems, although the highest density state ofthe art storage systems are more likely to be perpendicular recordingsystems. Heating of the media surface has been accomplished by a numberof techniques such as focused laser beams or near field optical sources.

U.S. Pat. No. 6,999,384 to Stancil et al., which is herein incorporatedby reference, discloses near field heating of a magnetic medium.

What is needed is a way to further improve TAR systems.

SUMMARY OF THE INVENTION

An apparatus according to one embodiment includes a near fieldtransducer comprising a conductive metal film and an optical waveguidefor illumination of the near field transducer, a light guiding corelayer of the optical waveguide being spaced from the near fieldtransducer by less than about 100 nanometers and greater than 0nanometers; wherein a longitudinal axis of the optical waveguide issubstantially perpendicular to an air bearing surface.

An apparatus according to another embodiment includes a near fieldtransducer comprising a conductive metal film; and an optical waveguidefor illumination of the near field transducer, a light guiding corelayer of the optical waveguide being spaced from the near fieldtransducer by less than about 100 nanometers, wherein a longitudinalaxis of the optical waveguide is substantially perpendicular to an airbearing surface.

A method according to another embodiment includes forming a near fieldtransducer structure having an air bearing surface (ABS) side and asecond side opposite the ABS side; forming a cladding layer adjacent thesecond side of the near field transducer structure, wherein a portion ofthe cladding layer extends along the near field transducer structure;and forming a core layer adjacent to the portion of the cladding layerextending along the near field transducer structure and above a secondportion of the cladding layer, the core layer being separated from thenear field transducer via the cladding layer, wherein a longitudinalaxis of the core layer is substantially perpendicular to the ABS side ofthe near field transducer.

A method according to another embodiment includes forming a lowercladding layer; forming a near field transducer structure above thelower cladding layer; forming a second cladding layer adjacent the nearfield transducer structure and above the lower cladding layer, wherein aportion of the second cladding layer extends along the near fieldtransducer structure; and forming a core layer above the second claddinglayer.

Any of these embodiments may be implemented in a magnetic data storagesystem such as a disk drive system, which may include a magnetic head, adrive mechanism for passing a magnetic medium (e.g., hard disk) over themagnetic head, and a controller electrically coupled to the magnetichead.

Other aspects and advantages of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and advantages of the presentinvention, as well as the preferred mode of use, reference should bemade to the following detailed description read in conjunction with theaccompanying drawings.

FIG. 1 is a simplified drawing of a magnetic recording disk drivesystem.

FIG. 2A is a schematic representation in section of a recording mediumutilizing a longitudinal recording format.

FIG. 2B is a schematic representation of a conventional magneticrecording head and recording medium combination for longitudinalrecording as in FIG. 2A.

FIG. 2C is a magnetic recording medium utilizing a perpendicularrecording format.

FIG. 2D is a schematic representation of a recording head and recordingmedium combination for perpendicular recording on one side.

FIG. 2E is a schematic representation of a recording apparatus adaptedfor recording separately on both sides of the medium.

FIG. 3A is a cross-sectional view of one particular embodiment of aperpendicular magnetic head with helical coils.

FIG. 3B is a cross-sectional view of one particular embodiment of apiggyback magnetic head with helical coils.

FIG. 4A is a cross-sectional view of one particular embodiment of aperpendicular magnetic head with looped coils.

FIG. 4B is a cross-sectional view of one particular embodiment of apiggyback magnetic head with looped coils.

FIG. 5A is a partial cross section view of a thin film perpendicularwrite head design according to one embodiment.

FIG. 5B is a partial cross section expanded view of detail 5B in FIG.5A, in accordance with one embodiment.

FIG. 6A is a top view of a near field transducer according to oneembodiment.

FIG. 6B is a side view of a structure including a near field transduceraccording to one embodiment.

FIG. 7A is a side view of a structure including a near field transduceraccording to one embodiment.

FIG. 7B is a top view of a lower portion of a structure taken from Line7B in FIG. 7A according to one embodiment.

FIG. 7C is a top, view of an upper portion of a structure taken fromLine 7C in FIG. 7A according to one embodiment.

FIG. 7D is a trailing view of a main pole according to one embodiment.

FIG. 7E is a top view of a main pole according to one embodiment.

FIG. 8A is a side view of a structure including a near field transduceraccording to one embodiment.

FIG. 8B is a side view of a structure including a near field transduceraccording to one embodiment.

FIG. 9A is a top view of a near field transducer according to oneembodiment.

FIG. 9B is a side view of a structure including a near field transduceraccording to one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified.

The following description discloses several preferred embodiments ofdisk-based storage systems and/or related systems and methods, as wellas operation and/or component parts thereof.

In one general embodiment, an apparatus comprises a near fieldtransducer comprising a conductive metal film having a main body and aridge extending from the main body; and an optical waveguide forillumination of the near field transducer, a light guiding core layer ofthe optical waveguide being spaced from the near field transducer byless than about 100 nanometers and greater than 0 nanometers.

In another general embodiment, an apparatus comprises a near fieldtransducer comprising a conductive metal film; and an optical waveguidefor illumination of the near field transducer, a light guiding corelayer of the optical waveguide being spaced from the near fieldtransducer by less than about 100 nanometers and greater than about 10nanometers.

In yet another general embodiment, a method comprises forming a nearfield transducer structure; removing a portion of the near fieldtransducer structure; forming a cladding layer adjacent a remainingportion of the near field transducer structure, wherein a portion of thecladding layer extends along the remaining portion of the near fieldtransducer structure; and forming a core layer above the cladding layer.

In another general embodiment, a method comprises forming a lowercladding layer; forming a near field transducer structure above thelower cladding layer; removing a portion of the near field transducerstructure; forming a second cladding layer adjacent a remaining portionof the near field transducer structure and above the lower claddinglayer, wherein a portion of the second cladding layer extends along theremaining portion of the near field transducer structure; and forming acore layer above the second cladding layer.

Referring now to FIG. 1, there is shown a disk drive 100 in accordancewith one embodiment of the present invention. As shown in FIG. 1, atleast one rotatable magnetic disk 112 is supported on a spindle 114 androtated by a disk drive motor 118. The magnetic recording on each diskis typically in the form of an annular pattern of concentric data tracks(not shown) on the disk 112.

At least one slider 113 is positioned near the disk 112, each slider 113supporting one or more magnetic read/write heads 121. As the diskrotates, slider 113 is moved radially in and out over disk surface 122so that heads 121 may access different tracks of the disk where desireddata are recorded and/or to be written. Each slider 113 is attached toan actuator arm 119 by means of a suspension 115. The suspension 115provides a slight spring force which biases slider 113 against the disksurface 122. Each actuator an 119 is attached to an actuator 127. Theactuator 127 as shown in FIG. 1 may be a voice coil motor (VCM). The VCMcomprises a coil movable within a fixed magnetic field, the directionand speed of the coil movements being controlled by the motor currentsignals supplied by controller 129.

During operation of the disk storage system, the rotation of disk 112generates an air bearing between slider 113 and disk surface 122 whichexerts an upward force or lift on the slider. The air bearing thuscounter-balances the slight spring force of suspension 115 and supportsslider 113 off and slightly above the disk surface by a small,substantially constant spacing during normal operation. Note that insome embodiments, the slider 113 may slide along the disk surface 122.

The various components of the disk storage system are controlled inoperation by control signals generated by control unit 129, such asaccess control signals and internal clock signals. Typically, controlunit 129 comprises logic control circuits, storage (e.g., memory), and amicroprocessor. The control unit 129 generates control signals tocontrol various system operations such as drive motor control signals online 123 and head position and seek control signals on line 128. Thecontrol signals on line 128 provide the desired current profiles tooptimally move and position slider 113 to the desired data track on disk112. Read and write signals are communicated to and from read/writeheads 121 by way of recording channel 125.

The above description of a typical magnetic disk storage system, and theaccompanying illustration of FIG. 1 is for representation purposes only.It should be apparent that disk storage systems may contain a largenumber of disks and actuators, and each actuator may support a number ofsliders.

An interface may also be provided for communication between the diskdrive and a host (integral or external) to send and receive the data andfor controlling the operation of the disk drive and communicating thestatus of the disk drive to the host, all as will be understood by thoseof skill in the art.

In a typical head, an inductive write head includes a coil layerembedded in one or more insulation layers (insulation stack), theinsulation stack being located between first and second pole piecelayers. A gap is formed between the first and second pole piece layersby a gap layer at an air bearing surface (ABS) of the write head. Thepole piece layers may be connected at a back gap. Currents are conductedthrough the coil layer, which produce magnetic fields in the polepieces. The magnetic fields fringe across the gap at the ABS for thepurpose of writing bits of magnetic field information in tracks onmoving media, such as in circular tracks on a rotating magnetic disk.

The second pole piece layer has a pole tip portion which extends fromthe ABS to a flare point and a yoke portion which extends from the flarepoint to the back gap. The flare point is where the second pole piecebegins to widen (flare) to form the yoke. The placement of the flarepoint directly affects the magnitude of the magnetic field produced towrite information on the recording medium.

FIG. 2A illustrates, schematically, a conventional recording medium suchas used with magnetic disc recording systems, such as that shown inFIG. 1. This medium is utilized for recording magnetic domains in orparallel to the plane of the medium itself. The recording medium, arecording disc in this instance, comprises basically a supportingsubstrate 200 of a suitable non-magnetic material such as glass, with anoverlying coating 202 of a suitable and conventional magnetic layer.

FIG. 2B shows the operative relationship between a conventionalrecording/playback head 204, which may preferably be a thin film head,and a conventional recording medium, such as that of FIG. 2A.

FIG. 2C illustrates, schematically, the orientation of magnetic domainssubstantially perpendicular to the surface of a recording medium as usedwith magnetic disc recording systems, such as that shown in FIG. 1. Forsuch perpendicular recording the medium typically includes an underlayer 212 of a material having a high magnetic permeability. This underlayer 212 is then provided with an overlying coating 214 of magneticmaterial preferably having a high coercivity relative to the under layer212.

FIG. 2D illustrates the operative relationship between a perpendicularhead 218 and a recording medium. The recording medium illustrated inFIG. 2D includes both the high permeability under layer 212 and theoverlying coating 214 of magnetic material described with respect toFIG. 2C above. However, both of these layers 212 and 214 are shownapplied to a suitable substrate 216. Typically there is also anadditional layer (not shown) called an “exchange-break” layer or“interlayer” between layers 212 and 214.

In this structure, the magnetic lines of flux extending between thepoles of the perpendicular head 218 loop into and out of the overlyingcoating 214 of the recording medium with the high permeability underlayer 212 of the recording medium causing the lines of flux to passthrough the overlying coating 214 in a direction generally perpendicularto the surface of the medium to record information in the overlyingcoating 214 of magnetic material preferably having a high coercivityrelative to the under layer 212 in the form of magnetic domains havingtheir axes of magnetization substantially perpendicular to the surfaceof the medium. The flux is channeled by the soft underlying coating 212back to the return layer (P1) of the head 218.

FIG. 2E illustrates a similar structure in which the substrate 216carries the layers 212 and 214 on each of its two opposed sides, withsuitable recording heads 218 positioned adjacent the outer surface ofthe magnetic coating 214 on each side of the medium, allowing forrecording on each side of the medium.

FIG. 3A is a cross-sectional view of a perpendicular magnetic head. InFIG. 3A, helical coils 310 and 312 are used to create magnetic flux inthe stitch pole 308, which then delivers that flux to the main pole 306.Coils 310 indicate coils extending out from the page, while coils 312indicate coils extending into the page. Stitch pole 308 may be recessedfrom the ABS 318. Insulation 316 surrounds the coils and may providesupport for some of the elements. The direction of the media travel, asindicated by the arrow to the right of the structure, moves the mediapast the lower return pole 314 first, then past the stitch pole 308,main pole 306, trailing shield 304 which may be connected to the wraparound shield (not shown), and finally past the upper return pole 302.Each of these components may have a portion in contact with the ABS 318.The ABS 318 is indicated across the right side of the structure.

Perpendicular writing is achieved by forcing flux through the stitchpole 308 into the main pole 306 and then to the surface of the diskpositioned towards the ABS 318.

FIG. 3B illustrates a piggyback magnetic head having similar features tothe head of FIG. 3A. Two shields 304, 314 flank the stitch pole 308 andmain pole 306. Also sensor shields 322, 324 are shown. The sensor 326 istypically positioned between the sensor shields 322, 324.

FIG. 4A is a schematic diagram of one embodiment which uses looped coils410, sometimes referred to as a pancake configuration, to provide fluxto the stitch pole 408. The stitch pole then provides this flux to themain pole 406. In this orientation, the lower return pole is optional.Insulation 416 surrounds the coils 410, and may provide support for thestitch pole 408 and main pole 406. The stitch pole may be recessed fromthe ABS 418. The direction of the media travel, as indicated by thearrow to the right of the structure, moves the media past the stitchpole 408, main pole 406, trailing shield 404 which may be connected tothe wrap around shield (not shown), and finally past the upper returnpole 402 (all of which may or may not have a portion in contact with theABS 418). The ABS 418 is indicated across the right side of thestructure. The trailing shield 404 may be in contact with the main pole406 in some embodiments.

FIG. 4B illustrates another type of piggyback magnetic head havingsimilar features to the head of FIG. 4A including looped coils 410,which loops around to form looped coils 412. Also, sensor shields 422,424 are shown. The sensor 426 is typically positioned between the sensorshields 422, 424.

In FIGS. 3B and 4B, an optional heater 328, 428, respectively, is shownnear the non-ABS side of the magnetic head. A heater 328, 428 may alsobe included in the magnetic heads shown in FIGS. 3A and 4A. The positionof this heater may vary based on design parameters such as where theprotrusion is desired, coefficients of thermal expansion of thesurrounding layers, etc.

Thermally assisted recording (TAR) is a method of recording informationonto a magnetic recording medium, such as a disk, tape, etc. One generalmotivation for this invention relates to the design of a recesseddielectric waveguide and integration with a near-field opticaltransducer for TAR. The waveguide core may be optimally recessed by adistance from the transducer and this space may be filled with low indexdielectric material leading to significant enhancement of the opticalefficiency. In one preferred embodiment, the low index dielectricmaterial in the recessed space may be deposited after fabrication of thenear-field transducer using an anisotropic deposition followed bydeposition of the high index core material.

According to some embodiments, for TAR to be realized, it may bebeneficial to confine heat to about a single data track (an exemplarydata track may be approximately 40 nm wide or smaller) with highefficiency. Candidate near-field optical sources typically use alow-loss metal (Au, Ag, Al, Cu, etc.) shaped in such a way as toconcentrate surface charge motion at a tip apex located at the sliderABS when light is incident. Oscillating tip charge may create an intensenear-field pattern, heating the disk. Sometimes, the metal structure cancreate resonant charge motion (surface plasmons) to further increaseintensity and disk heating. For example, when polarized light is alignedwith the corner of a triangular-shaped gold plate, an intense near fieldpattern may be created at that corner. Resonant charge motion may occurby adjusting the triangle size to match a surface plasmon frequency tothe incident light frequency. Another near-field transducer is the ridgeslot waveguide from microwave circuits applied to optical frequencies(also known as the C aperture). This shape may be characterized by fiveparameters including the metal thickness. Light polarization may bealigned with the ridge and incident light may concentrate surface chargeat the tip of the ridge.

Previously, a ridge waveguide in silver has been optimized at awavelength of 516 nm and a metal-to-metal fly-height of 8 nm. Also, farfield measurements obtained for various C aperture sizes indicate aspectral shift while narrow resonant behavior has been observed when apattern of ridges is used to excite surface plasmons around a long slotand enhance far field transmission. The majority of embodimentsdescribed herein relate to using a ridge waveguide of some kind toenhance the writing capabilities in TAR.

U.S. Pat. No. 6,999,384 to Stancil et al., incorporated by referenceabove, describes the phenomenon of near field heating of a magneticmedium in more detail.

Now referring to FIG. 5A, a partial cross section view 500 of a thinfilm perpendicular write head design incorporating an integratedaperture near field optical source is shown according to one embodiment.Of course, this embodiment may be used in conjunction with anystructures and systems described in any of the other figures. In orderto simplify and clarify the structures presented, spacing layers,insulating layers, and write coil layers may be omitted from thesubsequent figures and descriptions.

With continued reference to FIG. 5A, the write head comprises lowerreturn pole layer 502, back-gap layer(s) 504, upper return pole layer506, and upper pole tip layer 508. Lower return pole layer 502 may alsohave a lower pole tip (not shown) at the ABS. Layer 510 is an opticalwaveguide core, surrounded by cladding layers 512 according to someembodiments. Layers 510 and 512 may extend through at least a portion ofback-gap layer(s) 504. The components inside of Circle 5B are shown inan expanded view in FIG. 5B. Coil layers (not shown) and variousinsulating and spacer layers (not shown) might reside in the cavitybounded by the ABS, back-gap(s) 504, lower return pole 502, and upperbounding layers 506, 508, and 512 as would be recognized by those ofskill in the art. Layers 502, 504, 506, and 508 may be comprised of asuitable magnetic alloy or material, as would be known by one ofreasonable skill in the relevant art. Exemplary materials include Co,Ni, and/or Fe and combinations thereof. Layer 510 may be comprised of asuitable light transmitting material, as would be known by one ofreasonable skill in the relevant art. Exemplary materials preferablyinclude Ta₂O₅, and/or TiO₂. As shown, the core layer 510 hasapproximately uniform cross section along its length. As well known inthe art, the optical waveguide can have a number of other possibledesigns including a planar solid immersion mirror or planar solidimmersion lens which have a non-uniform core cross section along thewaveguide's length.

FIG. 5B is a partial cross section expanded view of detail 5B in FIG.5A, in accordance with one embodiment. Pole lip 516 is magneticallycoupled to upper pole tip layer 508, and to optional magnetic step layer514. Aperture 518 (also known as a ridge aperture), surrounding metallayer 520, and pole lip 516 comprise the near field aperture opticalsource (or near field transducer), which is supplied optical energy viaoptical waveguide core 510. Pole lip 516 and optional magnetic steplayer 514 may be comprised of a suitable magnetic alloy, such as Co, Fe,Ni, and/or combinations thereof. Metal layer 520 may be comprised of Cu,Au, Ag, and/or alloys thereof, etc.

With continued reference to FIG. 5B, cladding layer 512 thickness may benominally about 200 nm, but may be thicker or thinner depending on thedimensions of other layers in the structure. Optional magnetic steplayer 514 may have a nominal thickness (the dimension between layers 508and 510) of about 150 nm, and a nominal depth (as measured from layer516 to layer 512) of about 180 nm. Pole lip 516 may have a nominal depth(as measured from the ABS) approximately equal to that of layer 520,with the value being determined by the performance and properties of thenear field optical source (see examples below). The thickness of thepole lip 516 can vary from about 150 nm (with the optional magnetic steplayer 514) to about 1 micron, preferably between about 250 nm and about350 nm. The thickness of optical waveguide core layer 510 may benominally between about 200 nm and about 400 nm, sufficient to cover thethickness of the aperture 518 (see FIG. 6A).

Now referring to FIG. 6A, a top view of a near field transducer 620 isshown according to one embodiment. Of course, this embodiment may beused in conjunction with any structures and systems described in any ofthe other figures, such as FIGS. 1-5B. FIG. 6A is a top view of the nearfield transducer 620 while FIG. 6B is a side view of a structure 600including the near field transducer 620.

As shown in FIG. 6A, a near field transducer 620, which may include a Caperture 602, is included in the structure (600, FIG. 6B), and may bedescribed as a plasmonic device with a field enhancing ridge. The Caperture 602 may be surrounded by a conductive metal film 604, and bothof these components together may comprise the near field transducer 620,which may comprise metal film 604 having a main body and a ridgeextending from the main body. In some embodiments, the conductive metalfilm 604 may be generally non-triangular in shape.

In some embodiments, the metal film 604 may further comprise wingsextending from the main body. Further, a layer of magnetic material mayextend at least a portion of a distance between the wings. Note that theconductive metal film 604 may be formed of various layers, and is notnecessarily a unitarily-formed film.

The C aperture 602 may isolate the ridge on three sides, and may becomprised of SiO₂, Al₂O₃, or any other suitable material as would beknown to one of reasonable skill in the relevant art. The conductivemetal film 604 may be comprised of Au, Cu, Ag, and/or combinationsthereof, etc., or any other suitable material as would be known to oneof reasonable skill in the relevant art.

In some other embodiments, the metal film 604 may have an E-antenna(described in FIGS. 9A and 9B) formed therein in place of the Caperture.

The values of the several dimensions indicated in FIG. 6A may beadjusted according to specific needs of the application, and thefollowing dimensions are for example only, and in no way limit the scopeof the invention. Each dimension may be larger or smaller depending onthe dimensions of other layers in the structure 600. In someembodiments, the length of α₁ may be about equal to the length of α₂.Also, in some embodiments, the length of α₁ and/or α₂ may be preferablybetween about 10 nm and about 50 nm, for example about 30 nm.

In some embodiments, the length of α₃ may be preferably between about 10nm and about 50 nm, for example about 15 nm, and in some furtherembodiments, the length of α₃ may be about equal to half of the lengthof α₁ and/or α₂.

In some embodiments, the length of α₄ may be preferably between about 60nm and about 250 nm, for example about 130 nm.

In FIG. 6B, a side view of the structure 600 is shown according to oneembodiment. The C aperture 602 may be surrounded by a conductive metalfilm 604. The height β₂ of the C aperture 602 may be between about 30 nmand about 300 nm, and may be set according to a relationship with thewavelength of a light. Above the C aperture 602, a core layer 610 may beformed of TiO₂, Ta₂O₅, etc., or any other suitable material as would beknown to one of reasonable skill in the relevant art. The core layer 610may be insulated from the C aperture 602 by a thin layer of materialforming a recess 612, comprised of a low index material like Al₂O₃,SiO₂, etc. In some embodiments, the recess 612 and the C aperture 602may be comprised of the same material. In general, a low index materialcan be any material having an index below about 1.75.

In some embodiments, the near field transducer 620 may be separated fromthe optical waveguide, which may include the core layer 610 andsurrounding cladding layers, by a recess 612 having a thickness β₃ ofgreater than about 0 nm and less than or equal to about 100 nm. In otherapproaches, the optical waveguide may be spaced from the near fieldtransducer 620 by between about 100 nm and about 10 nm, by between about80 nm and about 10 nm, by between about 60 nm and about 10 nm, bybetween about 100 nm and about 20 nm, by between about 100 nm and about40 nm, etc.

With continued reference to FIG. 6B, an air gap 614 may be present belowthe near field transducer 620, with a thickness β₁ of between about 1 nmand about 50 nm, which may act as a gap between the head and a disksurface, including a recording layer 608. The recording layer 608 may beformed of any suitable material as would be known to one of reasonableskill in the relevant art, such as CoPt or FePt. Below the recordinglayer 608, a heatsink 606 may be formed, as would be known to one ofreasonable skill in the relevant art.

Other layers and combinations of layers may be used in the structure 600or the disk as would be used by one of ordinary skill in the relevantart, including insulating layers, adhesive layers, etc. In addition, anyof the layers described in relation to structure 600 may be comprised ofmultiple layers, which may or may not be of the same material.

Now referring to FIG. 7A, a cross section taken from the middle ofanother structure 700 is shown according to one embodiment. Thestructure 700 may be a magnetic head with near field transducer 714,possibly including a C aperture or E-antenna 602, comprising aconductive metal film (604, FIG. 7B), and an integrated waveguide,possibly for illumination of the near field transducer 714, with a lightguiding core layer 712 of the optical waveguide being spaced from thenear field transducer 714 by a distance β₃. Of course, this embodimentmay be used in conjunction with any structures and systems described inFIGS. 1-6B. The structure may include a main pole 704 which may becomprised of any material as would be known to one of reasonable skillin the relevant art, such as NiFe, CoFe, CoNiFe, etc. The main pole 704may have a step 708 formed near the lower portion of the main pole 704.In addition, the main pole 704 may have a lip 706 formed near the ABS716.

In some embodiments, the distance β₃ may be less than about 100 nm andgreater than about 10 nm. In other approaches, the optical waveguide maybe spaced from the near field transducer 714 by between about 80 nm andabout 10 nm, by between about 60 nm and about 10 nm, by between about100 nm and about 20 nm, by between about 100 nm and about 40 nm, etc.

Next to the main pole 704, a lower cladding layer 710 may be formedwhich may isolate the main pole 704 from light propagating in core layer712. The lower cladding layer 710 may be formed of any low index,isolating material as would be known to one of ordinary skill in therelevant art, such as Al₂O₃, SiO₂, etc. The gap or aperture betweenmetal film (604, FIG. 7B) and magnetic lip 706 may be filled with anyoptically transparent or nearly transparent material such as SiO₂,Al₂O₃, etc., as is well known to those skilled in the art.

In addition, the isolating layer may form a thin layer between the nearfield transducer 714 and the core layer 712 of the optical waveguide,forming a recess between the near field transducer 714 and the corelayer 712. This separation of the near field transducer 714 from thecore layer 712 causes the optical efficiency of the structure 700 tosignificantly improve.

The core layer 712 is generally used to deliver light energy to a disksurface, thereby inducing isolated heating of the disk surface. The corelayer 712 may be comprised of any high index material, such as TiO₂,Ta₂O₅, etc., or any other material as would be known by one of ordinaryskill in the relevant art. On top of core layer 712, a top claddinglayer 702 may be formed, from any material as would be known to one ofordinary skill in the relevant art, such as Al₂O₃, SiO₂, etc. Inaddition, a cladding layer 718 may be formed above the main pole 704.The lower cladding layer 710 may also form a recess between the opticalwaveguide and the near field transducer 714, according to someembodiments.

FIG. 7B shows an ABS view taken from Line 7B in FIG. 7A of the structure700 according to one embodiment. As shown, the main pole 704 may form amagnetic lip 706 that extends toward the near field transducer 714. Theaperture 602 may be surrounded on three sides by a conductive metal film604, such as Au, Ag, Cu, etc. The notch in the aperture 602 may also befilled with the conductive metal film 604. The three sides of the metalfilm 604 which is not in contact with the magnetic lip 706 may beadjacent to the cladding layer 702.

Typically, a near field transducer optical source consists of arectangular shaped aperture placed in an electrically conductive metalfilm. In some embodiments, the near field transducer may be a C apertureor E-antenna. Light of the appropriate frequency is directed onto theaperture/antenna and the surrounding metal film.

In the present embodiment, light is directed to the near fieldtransducer 714 which comprises the C aperture 602 and surrounding metalfilm 604, via optical waveguide core layer 712. Extending into thecenter portion of the C aperture 602 is an electrically conductiveridge, generally an extension of the surrounding metal film 604.Incident radiation, polarized in the direction parallel to the ridgeproduces a near-field light source which appears close to or at the endof the ridge, in the gap between the end of the ridge and the opposingboundary of the aperture 602. In the present embodiment, magnetic lip706 is located at this opposing boundary, placing the near field lightsource in close proximity to the magnetic lip 706.

Note that magnetic lip 706 makes up an integral component to themetallic region surrounding the C aperture 602. In near field lightsources of conventional construction, the entire metallic regionsurrounding the C aperture is comprised of highly conductive metals suchas Cu, Ag, or Au. Prior art modeling studies of the conventional Caperture indicated that a highly conductive metal was required tooptimize light output of the near field source, and it has been assumedthat the entire metal region surrounding C aperture needed to becomprised of a highly conductive material. This generally required thatany pole material be placed outside the conductive region surroundingthe aperture, limiting the proximity of optical heat source to the poletip, precluding the use of dual gradient recording. Studies performed inthe development of the present embodiment have uncovered the unexpecteddevelopment that a magnetic lip 706 of approximately the same height astransducer material 604, can be substituted for a portion of the highlyconductive layer 604 surrounding the C aperture 602, with minimal impacton the optical efficiency, provided that the magnetic lip 706 bordersaperture 602, and is located across from the end of the ridge. Thislocates the effective pole tip of the write head at very close proximityto the thermal region generated by a near field light source, which islocated between the end of the ridge and the edge of magnetic lip 706.

FIG. 7C shows a cross section view taken from Line 7C in FIG. 7A of thestructure 700 according to one embodiment. As shown at this positionaway from the ABS 716, the structure 700 may be generally referred to asan optical waveguide. A cladding layer 702 may surround three sides of astructure formed of the isolating layer 710 and the core layer 712,while another cladding layer 718 may be formed on the remaining side.The core layer 712 may have a rectangular cross section, or any othercross sectional profile as selected by one of ordinary skill in therelevant art, such as square, triangular, circular, etc. Other waveguidestructures may also be used, such as solid immersion mirrors, solidimmersion lenses, etc.

In each of FIGS. 7A-7C, the left most portion of the figure may extendfurther and may form more shapes and may include additional layers.Also, other layers and combinations of layers may be used in thestructure 700 as would be used by one of ordinary skill in the relevantart, including insulating layers, adhesive layers, etc. In addition, anyof the layers described in relation to structure 700 may be comprised ofmultiple layers, which may or may not be of the same material.

Now referring to FIG. 7D, a trailing view is shown of the main pole 704according to one embodiment. As shown, the main pole 704 may taperoutwardly from a lower portion. The height dimension ε₄ indicates theheight of the step (708, FIG. 7A), which may be between about 100 andabout 1000 nm, preferably about 500 nm. The height dimension ε₂indicates the height of the pole lip (706, FIG. 7A), which may bebetween about 20 nm and about 200 nm, preferably about 90 nm. Inaddition, the width dimension ε₃ indicates the width of the step (708,FIG. 7A), which may be between about 200 nm and about 2000 nm,preferably about 1000 nm. The width dimension ε₁ indicates the width ofthe pole lip (706, FIG. 7A), which may be between about 100 nm and about1000 nm, preferably about 600 nm.

Now referring to FIG. 7E, a partial ABS view of the main pole 704 isshown according to one embodiment. As can be seen, the main pole 704 mayhave a narrower portion and a thicker portion. According to someembodiments, the dimensions, ε₅ and ε₆ may be about equal. In addition,the dimensions ε₅ and ε₆ may be between about 200 and 2000 nm,preferably about 1000 nm. The dimension ε₇ may be between about 70 nmand about 700 nm, preferably about 350 nm. The dimension ε₈ may bebetween about 100 nm and about 1000 nm, preferably about 600 nm.

Each of the dimensions described in regard to FIGS. 7D and 7E or anyother embodiment, may be more or less, depending on the particular sizesand shapes of components in the head and system.

FIGS. 8A and 8B show two alternate structures which have a recess 802which may isolate the core layer 712 from the near field transducer 714according to specific embodiments. Of course, these embodiments may beused in conjunction with any structures and systems described in FIGS.1-7E. In FIG. 8A, the magnetic lip 706 and the near field transducer714, which in this embodiment comprises the conductive metal film 604and the aperture 602, may be formed before the cladding layer 710, andthen etched or ion milled to form a back wall. The recess 802 may thenbe formed as a single, continuous cladding layer 710, possibly throughanisotropic deposition of the lower cladding material to form thecladding layer 710, followed by deposition of the core material to formthe core layer 712. Chemical-mechanical polishing (CMP) may be used toplanarize the structure and may remove cladding and core material abovethe near field transducer 714.

In FIG. 8B, the recess 802 may be formed of a cladding layer 806 whichmay be a separate layer from the lower cladding layer 804. In thisembodiment, the majority of the lower cladding layer 804 may be formed,and the near field transducer 714, which in this embodiment comprisesthe conductive metal film 604 and the aperture 602, may be formed abovethe lower cladding layer 804. The magnetic lip 706 is formed on top ofthe near field transducer 714. The near field transducer 714 andmagnetic lip 706 may then be etched or ion milled to form a back wall,and then the cladding layer 806 may be formed, possibly throughisotropic deposition of additional cladding material, after the nearfield transducer 714 and magnetic lip 706 is formed. Then the core layer712 may be formed, possibly through deposition of core material,followed by CMP to planarize the structure and remove cladding and corematerial above the transducer.

Also included in the structure in FIG. 8B is the pole step 708, and pole704, which may be formed of the same magnetic material in one or severalprocessing steps. Between the pole step 708 and the core layer 712, atop cladding layer 710 may be formed.

In some embodiments, at least one cladding layer 806 may be positionedbetween the core layer 712 and the near field transducer 714. Further,at least one of the cladding layers 806 may be directly adjacent a sideof the core layer 712 extending parallel to an axis of the core layer712 and a side of the core layer 712 extending perpendicular to the axisof the core layer 712. Also, at least one of the cladding layers 804 mayextend below the near field transducer 714, as shown in FIG. 8B.

Now, with reference to FIG. 8A, a method is described for forming astructure. The method comprises forming a near field transducer 714structure. A portion of the near field transducer 714 may be removed,through etching or ion milling or some other technique known to one ofskill in the relevant art. Once the back wall of the near fieldtransducer 714 is formed, a cladding layer 710 may be formed adjacent toa remaining portion of the near field transducer 714 structure, whereina portion of the cladding layer 710 may extend along the remainingportion of the near field transducer 714 structure. Now, a core layer712 may be formed above the cladding layer 710.

In some embodiments, the near field transducer 714 may have a C aperture602 formed therein. In other embodiments, the near field transducer 714may have an E antenna (described below) formed therein.

In some embodiments, the method includes forming a cladding layer whichmay enclose the core layer 712, and at least one cladding layers may bepositioned between the core layer 712 and the near field transducer 714.

In some additional embodiments, as shown in FIG. 8B, a cladding layer804 may extend below the near field transducer 714. In addition, thecore layer 712 may be positioned above two cladding layers 804, 806.

In some embodiments, at least a portion of the near field transducer 714may include magnetic material, such as Fe, Ni, Co, and/or combinationsthereof, etc.

FIGS. 9A and 9B show an alternative embodiment called an E-Antenna 902.Of course, this embodiment may be used in conjunction with anystructures and systems described in FIGS. 1-8B. The E-Antenna 902 mayact as a plasmonic device with a field enhancing ridge 908, similar tothe C aperture described earlier. The E-Antenna 902 is comprised of foursections, separated by dashed lines in FIG. 9A: a body section 910, twowing sections 906, and a notch section 908. Each of these sections maybe formed in a single process, or may be formed separately and thenconnected. The E-Antenna 902 may be comprised of any low loss metal suchas Au, Cu, Ag, etc., as is known to one of ordinary skill in therelevant art. In particular, the body 910 and notch 908 may preferablybe comprised of Au, Cu, Ag, and/or combinations thereof. A dielectriclayer 904 may surround the E-antenna 902, and may be comprised of anysuitable material as would be known to one of reasonable skill in therelevant art, such as SiO₂.

In FIG. 9A, four dimensions are shown. Dimension φ₁ may be between about5 nm and about 50 nm, preferably about 30 nm. Dimension φ₂ may be abouthalf of dimension φ₁, and in some embodiments, dimension φ₂ may betweenabout 5 nm and about 50 nm. Dimension φ₃ may be between about 25 nm andabout 250 nm, preferably about 125 nm. In some embodiments, dimension φ₃and dimension φ₄ may be about equal. In some embodiments, dimension φ₄may be between about 25 nm and about 250 nm, preferably about 125 nm.The wing sections 906 should be large enough to act as a chargereservoir for the plasmon formed in the body.

Now referring to FIG. 9B, a side view of the E-antenna 902 is shownaccording to one embodiment. The E-antenna may have a thickness β₂ ofbetween about 30 nm and about 300 nm, and may be set according to arelationship with the wavelength of a light. An air gap 614 may beformed below the E-antenna 902, with a thickness β₁ of between about 1nm and about 50 nm, which may act as a gap between the head and a disksurface, including a recording layer 608. Below the air gap 614, arecording layer 608 may be formed of any suitable high magneticanisotropy material as would be known to one of reasonable skill in therelevant art, such as CoPt or FePt. Below the recording layer 608, aheatsink 606 may be formed, as would be known to one of reasonable skillin the relevant art. As shown in FIG. 9B, the dielectric layer 904 mayfill in the void spaces around the E-antenna 902.

It should be noted that methodology presented herein for at least someof the various embodiments may be implemented, in whole or in part, incomputer hardware, software, by hand, using specialty equipment, etc.and combinations thereof.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of an embodiment of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

1. An apparatus, comprising: a near field transducer comprising aconductive metal film; and an optical waveguide for illumination of thenear field transducer, a light guiding core layer of the opticalwaveguide being spaced from the near field transducer by less than about100 nanometers and greater than 0 nanometers, wherein a longitudinalaxis of the optical waveguide is substantially perpendicular to an airbearing surface.
 2. The apparatus as recited in claim 1, wherein theconductive metal film has a C aperture formed therein.
 3. The apparatusas recited in claim 1, wherein the conductive metal film has an E shape.4. The apparatus as recited in claim 1, wherein the conductive metalfilm includes wings extending from the main body.
 5. The apparatus asrecited in claim 4, further comprising a layer of magnetic materialextending at least a portion of a distance between the wings.
 6. Theapparatus as recited in claim 1, wherein the conductive metal film isgenerally non-triangular.
 7. The apparatus as recited in claim 1,wherein the optical waveguide is spaced from the near field transducerby between about 100 nanometers and about 10 nanometers.
 8. Theapparatus as recited in claim 1, wherein the optical waveguide furthercomprises cladding layers enclosing the core layer.
 9. The apparatus asrecited in claim 8, wherein at least one of the cladding layers ispositioned in a location selected from a group consisting of between thecore layer and the near field transducer, and below the near fieldtransducer.
 10. The apparatus as recited in claim 9, wherein the atleast one of the cladding layers is directly adjacent a side of the corelayer extending parallel to an axis of the core layer and a side of thecore layer extending perpendicular to the axis of the core layer. 11.The apparatus as recited in claim 1, wherein at least a portion of thenear field transducer is positioned between the air bearing surface andthe core layer.
 12. The apparatus as recited in claim 1, furthercomprising: a magnetic head, the near field transducer being in themagnetic head; a magnetic medium; a drive mechanism for passing themagnetic medium over the magnetic head; and a controller electricallycoupled to the magnetic head for controlling operation of the magnetichead.
 13. An apparatus, comprising: a near field transducer comprising aconductive metal film; and an optical waveguide for illumination of thenear field transducer, a light guiding core layer of the opticalwaveguide being spaced from the near field transducer by less than about100 nanometers, wherein a longitudinal axis of the optical waveguide issubstantially perpendicular to an air bearing surface.
 14. The apparatusas recited in claim 13, wherein the conductive metal film has at leastone of a C aperture formed therein and an E shape.
 15. The apparatus asrecited in claim 13, wherein at least a portion of the near fieldtransducer is positioned between the air bearing surface and the corelayer.
 16. The apparatus as recited in claim 13, wherein the opticalwaveguide further comprises cladding layers enclosing the core layer,wherein at least one of the cladding layers is positioned between thecore layer and the near field transducer.
 17. The apparatus as recitedin claim 13, further comprising: a magnetic head, the near fieldtransducer being in the magnetic head; a magnetic medium; a drivemechanism for passing the magnetic medium over the magnetic head; and acontroller electrically coupled to the magnetic head for controllingoperation of the magnetic head.
 18. The apparatus as recited in claim16, wherein the optical waveguide further comprises cladding layersenclosing the core layer, wherein the core layer is above two claddinglayers.
 19. A method, comprising: forming a near field transducerstructure having an air bearing surface (ABS) side and a second sideopposite the ABS side; forming a cladding layer adjacent the second sideof the near field transducer structure, wherein a portion of thecladding layer extends along the near field transducer structure; andforming a core layer adjacent to the portion of the cladding layerextending along the near field transducer structure and above a secondportion of the cladding layer., the core layer being separated from thenear field transducer via the cladding layer, wherein a longitudinalaxis of the core layer is substantially perpendicular to the ABS side ofthe near field transducer.
 20. The method as recited in claim 19,wherein the near field transducer structure has at least one of a Caperture formed therein and an E shape.
 21. The method as recited inclaim 19, wherein at least a portion of the near field transducer ispositioned between the air bearing surface and the core layer.
 22. Themethod as recited in claim 19, wherein at least a portion of the nearfield transducer structure includes a magnetic material.
 23. A method,comprising: forming a lower cladding layer; forming a near fieldtransducer structure above the lower cladding layer; forming a secondcladding layer adjacent the near field transducer structure and abovethe lower cladding layer, wherein a portion of the second cladding layerextends along the near field transducer structure; and forming a corelayer above the second cladding layer.
 24. The method as recited inclaim 23, wherein the near field transducer structure has a C apertureformed therein, wherein a longitudinal axis of the core layer issubstantially perpendicular to an ABS side of the near field transducer.25. The method as recited in claim 23, wherein the near field transducerstructure includes a conductive metal film having an E shape.